1. Field of the Invention
The present invention relates to a clip assembly, and particularly to a clip assembly which readily attaches a heat sink to an electronic device.
2. The Related Art
A heat sink is usually mounted in contact with an electronic device for removing heat therefrom. Various means have been used for attaching heat sinks to be in intimate thermal contact with electronic devices. Common means include using adhesives or clips. However, coefficients of thermal expansion of heat sinks are generally different from coefficients of thermal expansion of adhesives. Thus, a heat sink fastened by adhesive is easily separated from the electronic device during transportation. Moreover, it is extremely difficult to remove such heat sink from the electronic device. This makes repair or replacement of the components impractical.
Conventional clips also pose problems for manufacturers. For example, referring to FIGS. 10 and 11, a conventional heat dissipating assembly comprises a heat sink 2 and a plurality of T-shaped clips 1. Each of two sides of the heat sink 2 defines a slot 22 therein. Each clip 1 comprises a cross arm 12, and a leg 14 depending from a middle portion of the cross arm 12. The distal end of the leg 14 defines a catch 16. In assembly, the cross arm 12 of each clip 1 is received in the slot 22 of the heat sink 2. The heat sink 2 is placed on an electronic device 3, with the catch 16 of the clip 1 engaging with a lower portion of the electronic device 3.
However, this conventional clip assembly has many shortcomings. First, the clip must be manufactured to a given size required by the design of a particular heat sink. Every differently sized heat sink requires a new differently sized clip. Secondly, the engaging force of the clip is limited. Thirdly, the process of inserting the clip into the slot requires great precision of movement. The process often results in deformation or even breakage of the clip. Fourthly, the clip does not prevent the heat sink from moving in a lateral direction relative to the electronic device. U.S. Pat. No. 5,730,210 discloses a single fastening bolt cooperating with a spring to fasten a heat sink to the CPU on the mother board. This type design also requires unconformable laborious forcible insertion to have the inherent expansion head of the bolt extend through the fixing hole in the mother board for retention.
A new heat sink clip assembly is desired to overcome the above-mentioned problems of the prior art.